Osmotic caplet

ABSTRACT

An osmotic caplet is disclosed comprising an osmotic caplet exit for delivering a preselected dose of drug to a patient in need of therapy.

This application is a division of application Ser. No. 07/970,519, filedNov. 2, 1992, and benefit of the filing date of said earlier filedapplication is claimed under 35 U.S.C. § 120.

This invention pertains to an osmotic caplet. More particularly, thisinvention relates to an improvement in an osmotic caplet. The osmoticcaplet comprises an improvement in the drug flow dynamics of the capletgoverned by the ratio of delivery at least one delivery orifice or aplurality of orifices area A₁ to the caplet's internal cross-sectionarea πr², to provide a means for delivering substantially one-hundredpercent of the drug from the osmotic caplet. The invention concerns alsoa method for increasing the bioavailability of a drug by providing anosmotic caplet that delivers substantially one-hundred percent of a drugfrom the osmotic caplet, and substantially eliminate the start-up timeof the delivery.

BACKGROUND OF THE INVENTION

Osmotic dosage forms for delivering a drug to a fluid environment of useare known to the drug dispensing art. For example, U.S. Pat. No.3,845,770 issued to Theeuwes and Higuchi, and in U.S. Pat. No.3,916,899, issued to the same patentees, Theeuwes and Higuchi, anosmotic dosage form is disclosed comprising a semipermeable wall thatsurrounds a compartment comprising a drug. The wall is permeable to thepassage of fluid and there is a passageway through the wall fordelivering the drug from the dosage form. The dosage forms of thesepatents, release the drug by fluid being imbibed through the wall intothe compartment at a rate determined by the permeability of the wall andthe osmotic pressure gradient across the wall to produce a solution ofdrug that is dispensed through the passageway from the dosage form.These dosage forms are extraordinarily effective for delivering a drugthat exhibits an osmotic pressure gradient across the wall against thefluid. The dosage forms are effective also for delivering a drug mixedwith an osmotically effective solute that is soluble in the fluid andexhibits an osmotic pressure gradient across the wall against an aqueousfluid.

A quantum improvement in osmotic dosage forms was presented to themedical and pharmaceutical dispensing art by inventor Theeuwes in U.S.Pat. Nos. 4,111,202; 4,111,203; and 4,203,439. In these patents, thedelivery kinetics of the dosage form were enhanced for delivering a drugwith varying degrees of solubility in an aqueous fluid. The kinetics areimproved by manufacturing the dosage form with a drug compartment and anosmotic compartment separated by a film. These dosage forms deliver thedrug by fluid being imbibed through the wall into the osmoticcompartment producing a solution that causes the film to move and act asa driving force. The driving force pushes the drug through a smallpassageway from the dosage form.

A pioneer advancement in osmotic dosage forms was made by co-inventorsCortese and Theeuwes in U.S. Pat. No. 4,327,725 and by co-is inventorsWong, Barclay, Deters and Theeuwes in U.S. Pat. No. 4,612,008. Theosmotic dosage form in these patents comprise a semipermeable wall thatsurrounds a compartment. The compartment contains a drug formulation andan expandable hydrogel. In operation, fluid is imbibed into thecompartment where it contacts the drug formulation; thereby forming adispensable formulation that is pushed by the expanding hydrogel fromthe dosage form.

A further and unexpected contribution to the drug dispensing art wasprovided by co-inventors Deters, Theeuwes, Mullins and Eckenhoff in U.S.Pat. No. 4,627,850. In this patent, the inventors provided an osmoticcapsule comprising a wall capsulating and containing a drug formulation.The drug formulation is delivered through a very small orificemanufactured without any expressed ratio to the dimensions of theosmotic capsule. The osmotic capsule of this patent delivers aneffective dose of drug over time.

The osmotic dosage forms described in the above patents operatesuccessfully for their intended use and they deliver many difficult todeliver drugs for their intended therapeutic effects. Now, it has beenobserved, while these dosage forms are very effective and provide manyadvantages for delivering drugs for their intended therapy, there are ashort comings associated with these dosage forms. In one manufacture,for example, these prior art dosage forms often embrace a conventionaltablet shape that inherently retains or entraps drug in the inner topsurface or within inner corners of the dosage form. In anothermanufacture, for example, the prior art dosage form embraces aconventional capsule shape comprising an inner configuration thatentraps drug or restricts the flow of drug from the capsule in theimmediate interior region adjacent to the orifice of the capsule; and inanother instance, the drug is not delivered immediately and was delayedfor hours before delivery of the drug.

It will be appreciated by those versed in the art in the light of theabove presentation, that if an osmotic dosage form is provided that isessentially-free of the short comings known to the prior art, such anosmotic dosage form that would have a positive practical valve and itwould also represent an advancement in the drug delivery art. Thepresent invention advances the state of the drug delivery art byproviding a novel and unique dosage form manufactured as an osmoticcaplet for optimizing therapy by delivering essentially the full dose ofdrug present in the osmotic caplet. The osmotic caplet administers thedrug at a programmed and controlled rate per unit time over a prolongedperiod of time. The osmotic caplet provides continuous over theadministration of the drug, and the osmotic caplet maintains thiscontrol over an extended period of time.

OBJECT OF THE INVENTION

Accordingly, it is an immediate object of this invention to provide adosage form manufactured as an osmotic caplet for delivering a drug, andwhich osmotic caplet overcomes the limitations associated with the priorart.

Another object of the invention is to provide an osmotic caplet that canhouse a dose of drug and deliver essentially all of the drug forproviding the intended therapy of the drug.

Another object of the invention is to make available an improvement inan osmotic caplet, wherein the improvement comprises means formaximizing the amount of drug delivered from the osmotic caplet byproviding an internal convex surface that surrounds the orifice of thedelivery system.

Another object of the invention is to make available an osmotic capletcharacterized by an improvement in flow dynamics governed by a ratio oforifice diameter D₁ to an internal caplet diameter D₂ for increasing thedose of drug delivered thereby substantially eliminating drug entrapmentwithin the caplet.

Another object of the invention is to make available an osmotic capletcomprising means for enhancing the hydrodynamic drug delivery propertiesof the caplet by providing a caplet with a physical structure free ofcorners thereby eliminating residual drug retained in the corners of thecaplet at the termination of a drug delivery period.

Another object of the invention is to make available a caplet that istasteless, easily administered, easier to swallow than tablets, is solidand oblong-shaped with a curved lead end for enhancing the delivery ofthe medicament comprising the caplet.

Another object of this invention is to make available a solid-oblongosmotic tablet designed as an osmotic caplet with enhanced drugbioavailability for oral administration to a patient in need of drugtherapy.

Another object of this invention is to provide an osmotic caplet fordelivering in vivo a drug that is difficult to deliver and now can bedelivered by the osmotic caplet of this invention in a therapeuticallyeffective dose per unit time over time.

Another object of this invention is to provide an osmotic caplet foradministering a drug to the gastrointestinal tract by making availablean osmotic caplet comprising at least one wall that maintains itsintegrity in the gastrointestinal tract during the osmotic caplettransit through the gastrointestinal tract.

Another object of the invention is to provide an osmotic capletcomprising a wall capleting a solid drug formulation that optionallyincludes a pharmaceutically acceptable carrier, which drug is deliveredby the osmotic caplet at meaningful and useful therapeutic rates over aprolonged period of time.

Another object of the invention is to make available an osmotic capletcomprising at least one or a plurality of osmotic caplet orifices of anyshape provided the number of caplet orifices individually or totallyadded together is a certain fraction of the internal cross-section ofthe cylindrical osmotic caplet.

Another object of this invention is to provide an osmotic caplet systemsin which drug will be delivered immediately after ingestion without thedelay of start-up time characteristic of the prior art osmotic systemincluding osmotic push-pull systems.

Another object of this invention is to provide an osmotic capletcomprising an inner wall comprising of a water-swellable compositionthat swells at a controlled rate and encaplets a drug formulation, andan outer wall comprising a semipermeable composition that maintains itsphysical and chemical integrity and encaplets the inner wall.

Another object of the invention is to provide an osmotic capletcomprising a compartment containing a drug, which compartment issurrounded by a caplet wall comprising an osmotic-caplet orifice fordelivering a drug from the caplet over a prolonged period of time of atleast 15 minutes to thirty hours.

Another object of the invention is to provide an osmotic capletcomprising high drug loading of a drug, makeup once-a-day dosing of a upto 1200 mg in soluble drug in a single swallowable tablet.

Another object of the invention is to provide an osmotic capletcomprising a large osmotic caplet orifice for delivering insoluble drugformulations from the osmotic caplet.

Another object of the invention is to provide an osmotic capletcomprising an exterior instant drug-containing coat that releases thedrug immediately in vivo for immediate therapy.

Another object of the invention is to provide an osmotic capletcomprising at least one large orifice or a plurality of orificesequivalent to a large orifice for delivering an aqueous or biologicallyfluid insoluble drug from the osmotic caplet.

Another object of the invention is to provide an osmotic capletcomprising a cylindrical-shape semipermeable body comprising a curvedlead end with an accompanying orifice both designed for minimizing drugretention inside the osmotic caplet and a rear end.

Other objects, features and advantages of the invention will be moreapparent to those skilled in the art from the following specification,taken in conjunction with the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing figures, which are not drawn to scale, but are set forthto illustrate various manufacturers of the invention, the drawingfigures are as follows:

Drawing FIG. 1 illustrates one manufacture of an osmotic capletcomprising a continuous body with a pair of curved-rounded ends for bothincreasing the dose of drug delivered and for increasing theswallowability of the osmotic caplet;

Drawing FIG. 2 illustrates a longitudinal view of an osmotic capletcomprising an oblong-body terminating in rounded ends of reduceddiameter relative to the internal diameter of the oblong-body of theosmotic caplet, with the osmotic-caplet comprising a semipermeable wall;

Drawing FIG. 3 illustrates another manufacture of an osmotic capletprovided by the invention comprising an outer semipermeable wall and aninner gelatin wall with the caplet comprising at least one of a memberselected from the group consisting of an osmagent and an osmopolymer;

Drawing FIG. 4 illustrates another manufacture of an osmotic capletprovided by the invention comprising a dosage of drug in aninstant-release coat on the exterior of the caplet for immediate releasefor instant therapy; and,

In the drawings and in the specification, like parts in related figuresare identified by like numbers. The terms that appear earlier in thespecification and in the description of the drawing figures, as well asin embodiments thereof, are further detailed elsewhere in thedisclosure.

DETAILED DESCRIPTION OF THE DRAWING FIGURES.

Turning now to the drawing figures in detail, which drawing figures areexamples of an osmotic caplet provided by the invention, and whichexamples are not to be construed as limiting, one example of an osmoticcapsule is seen in drawing FIG. 1. In drawing FIG. 1, an osmotic caplet10 is seen comprising a body 11 and a lead end 12 and a trailing or rearend 13. Osmotic caplet 10 comprises a wall 14 that surrounds an internalcompartment, not seen in drawing FIG. 1.

Drawing FIG. 2 depicts the osmotic caplet 10 of drawing FIG. 1 in openedsection in drawing FIG. 2. The osmotic caplet 10 is illustrated as anoblong-shaped initially solid medicament invented for delivering themaximum dose of a drug. In a presently preferred manufacture, osmoticcaplet 10 is made comprising a single unit body 11 comprising a lead end12 and a rear end 13.

Osmotic caplet 10 comprises a wall 14 that surrounds an internalcompartment 15. Wall 14 is semipermeable, that is, wall 14 is permeableto the passage of a fluid, aqueous or biological fluids, present in anenvironment of use, such as an animal or human. Semipermeable wall 14 isnontoxic, substantially inert, and wall 14 maintains its physical andchemical integrity during the drug dispensing life of caplet 10. Thephrase, keeps its physical and chemical integrity, means wall 14 doesnot lose its physical and chemical integrity during the dispensing lifeof osmotic caplet 10.

Compartment 15 comprises an effective amount of drug 16 10 representedby dots. Drug 16 in one embodiment, is soluble to very soluble in anexternal fluid imbibed through semipermeable wall 14 into compartment15, and drug 16 exhibits an osmotic pressure gradient across wall 14.Drug 16, in another embodiment exhibits a limited solubility in fluidimbibed into compartment 15, and it exhibits a limited osmotic pressuregradient across wall 14. In this latter embodiment, drug 16 optionallymixed with an osmagent 17, presented as dashes, which osmagent 17 issoluble in the external fluid and it exhibits an osmotic pressuregradient across wall 14 for aiding in dispensing drug 16 from osmoticcaplet 10. Drug 16 can be present in compartment 15 with an optionalmember selected from the group consisting of a binder, dispersant,wetting agent, suspending agent, lubricant and dye, represented by wavyline 18. Representative of the members including suspending agents suchas colloidal magnesium, silicon dioxide, and calcium silicate; binderslike polyvinyl pyrrolidone, lubricants like magnesium stearate, andwetting agents such as fatty amines and fatty quaternary ammonium salts.A dye can be present in the compartment 15 for aiding in identifying adrug 16 present in caplet 10.

Osmotic dosage caplet 10 comprises a dispensing passageway 19 thatcommunicates the interior of compartment 15 with the exterior of soliddosage caplet 10. Dispensing passageway 19 is present in wall 14 in thearea where wall 14 is curved upward and outward from inside compartment15 for directing the maximum movement or flow of drug 16 fromcompartment 15. The curved, inside surface 20 and its continual rate ofcurved change eliminates sharp breaks, angularity, or corners therebysubstantially eliminating drug 16 entrapment at the inside surface 20 ofcaplet 10. The caplet drug delivery end 12 improves the flow profileresulting in a minimum to none amount of residual drug 16 in caplet 10.

Passageway 19 is a wide-passageway characterized by a geometrydistinctive from the conventional passageways of the prior art dosageforms. In the passageway 19, provided by this invention, the convexsurface 20 on the inside drug side of wall 12 possesses a radius ofcurvature r_(w), where r_(w) is equal to or larger than the radius ofosmotic caplet 10 designed as a cylinder with a cylindrical radius, r,but not exceeding 2r. The convex surface on the drug side 20 can be, inone embodiment, a cone shape. The height of the cone is at least equalor greater than the radius of the cylindrical portion of the caplet, r,and the preferred 2×r. In the preferred manufacture, passageway 19 ispositioned at the tip of the convex surface of the drug surface 20 ofwall 12. The passageway area optionally can be as large as thecylindrical cross-section area of the caplet, wherein the diameter is D.In the presently preferred dosage caplet 10, the area of the passagewayA₁ where A₁=0.1 to 0.9 is for a cylinder having a cylindricalcross-section area of πr². The dimensions of the osmotic caplet arepresently expressed in millimeters. Caplet passageway 19, in anothermanufacture comprises a multiplicity of orifices in the convex surface20, with the total area of the multiplicity of caplet passageways 19less than the cross-sectional area of the oblong osmotic caplet 10 atits widest area.

Dosage caplet 10 possessing the present passageway 19 exhibitsperformance characteristics exemplified by an absence of start-up timefor the osmotic caplet 10 for delivering drug 16; dosage caplet 10possesses the ability to deliver small doses and large doses of solubleand insoluble drugs from 300 nanograms to 1200 milligrams dose of drugover a 24 hour drug delivery period; dosage caplet 10 comprises internalcompartment for containing excipients helpful for delivering a peptideor protein, often protective agents and flux enhancers are co-deliveredwith the drug; and, dosage caplet 10 can deliver microparticles in whichthe small pellets are delivered to lessen mucosal irritation.

Drawing FIG. 3 depicts, in opened section, the osmotic caplet 10 ofdrawing FIG. 1. The osmotic caplet 10, of drawing FIG. 3, comprises abody 11 comprising lead end 12, rear end 13, wall 14 and compartment 15.Compartment 15 comprises drug 16 and an osmopolymer 21, or an expandabledriving member, identified by curve lines. Osmopolymer 21 is in contactwith the drug 16 composition. The drug 16 composition layer and theosmopolymer 21 layer operate in union for delivering the maximum dose ofdrug 16 through opened passageway 19. Compartment 15 optionallycomprises a member 18 selected from the group consisting of a binder,dispersant, wetting agent, suspending agent, lubricant, and dye. Osmoticcaplet 10 comprises additionally an internal wall 22 that facescompartment 15 and is in layered arrangement with the internal surfaceof wall 14. Internal wall 22 is non-toxic and it does not adverselyaffect drug 16 and other members 18 present in compartment 15. Internalwall 22 is permeable to the passageway of aqueous and biological fluids,and it comprises a hydrophilic polymeric composition that swells in thepresence of fluid imbibed into compartment 15.

Drawing FIG. 4 depicts, in opened section, the osmotic caplet 10.Osmotic caplet 10 comprises a body 11 comprising lead 12, trailing-end13, outside wall 14 and compartment 15. Compartment 15 comprises drug16, an osmagent 17, an osmopolymer 21, and a member 18 selected from thegroup consisting of a binder, dispersant, wetting agent, suspendingagent, lubricant and dye. Osmotic caplet 10, in drawing FIG. 4,additionally comprises a coat 23 on the exterior surface ofsemipermeable wall 14. Coat 23 comprises an aqueous or biologicalcomposition and it contains drug 24. Coat 23 comprising drug 24 providesdrug 24 for making available drug 24 instantly. In operation, whenosmotic caplet 10, is in a fluid environment, coat 23 dissolves orundergoes dissolution and concurrently delivers drug 24 to a biologicaldrug receptor. Coat 23 comprising drug 24 by providing immediate drug 24delivery, thereby overcomes any time that may be needed before drug 16is delivered from compartment 15 through passageway 19. Coat 23, uponhydration in an aqueous environment, operates independently ofcompartment 15, which compartment 15 delivers drug 16 by imbibing fluidthrough wall 14 and then hydro-osmotically delivering drug 16 fromosmotic caplet 10.

DETAILED DESCRIPTION OF THE INVENTION

Drawing FIGS. 1 through 4 are illustrative of osmotic caplet 10 that canbe manufactured according to the invention. In accordance with thepractice of this invention, osmotic caplet 10 is manufactured with asemipermeable wall 14 that does not adversely affect drug 16, thecomponents comprising osmotic caplet 10, and an animal, including ahuman patient host. Semipermeable wall 14 is permeable to the passage ofexternal fluid such as water and biological fluids, and it issubstantially impermeable to the passage of drug 16. The selectivelysemipermeable wall compositions are non-erodible, nontoxic, and they areinsoluble in fluids. Typical materials for forming wall 14 in oneembodiment are cellulose esters, cellulose ethers and celluloseester-ethers. These cellulosic polymers have a degree of substitution,D.S., on the anhydroglucose unit from greater than 0 up to 3 inclusive.By degree of substitution is meant the average number of hydroxyl groupsoriginally present on the anhydroglucose unit comprising the cellulosepolymer that are replaced by a substituting group. Representativematerials include a member selected from the group consisting ofcellulose acylate, cellulose diacylate, cellulose triacylate, celluloseacetate, cellulose diacetate, cellulose triacetate, mono, di andtricellulose alkanylates, mono, di and tricellulose aroylates, and thelike. Exemplary polymers include cellulose acetate having a D.S. up to 1and acetyl content up to 21%; cellulose acetate having an acetyl contentof 32 to 39.8%: cellulose diacetate having a D.S. of 1 of 2 and anacetyl content of 21 to 35%; cellulose triacetate having a D.S. of 2 to3 and an acetyl content of to 44.8%; and the like. More specificcellulosic polymers include cellulose propionate having a D.S. of 1.8and a propionyl content of 39.2 to 45% and a hydroxyl content of 2.8 to5.4%; cellulose acetate-butyrate having a D.S. of 1.8, and acetylcontent of 13 to 15% and a butyryl content of 34 to 39%; celluloseacetate butyrate having an acetyl content of 2 to 29%, a butyryl contentof 17 to 53% and a hydroxyl content of 0.5 to 4.7%; cellulosetriacylates having a D.S. of 2.9 to 3 such as cellulose trivalerate,cellulose trilaurate, cellulose tripalmitate, cellulose trisuccinate,and cellulose trioclanoate; cellulose diacylates having a D.S. of 2.2 to2.6 such as cellulose disuccinate, cellulose dipalmitate, cellulosedioclanoate, cellulose dipentale, and the like.

Additional semipermeable polymers for wall 12 include acetal-dehydedimethyl acetate, cellulose acetate ethyl carbamate, cellulose acetatephthalate for use in environments having a low pH, cellulose acetatemethyl carbamate, cellulose acetate dimethyl aminoacetate, semipermeablepolyamides, semipermeable polyurethanes, semipermeable sulfonatedpolystyrenes, cross-linked selectively semipermeable polymers formed bythe co-precipitation of a polyanion and a polycation as disclosed inU.S. Pat. Nos. 3,173,876; 3,276,586; 3,541,005; 3,541,006; and3,546,142; semipermeable polymers as disclosed by Loeb and Sourirajan inU.S. Pat. No. 3,133,132; lightly cross-linked polystyrene derivatives;cross-linked poly(sodium styrene sulfonate), cross-linkedpoly(vinylbenzyltrimethyl ammonium chloride), semipermeable polymersexhibiting a fluid permeability of 10⁻⁵ to 10⁻¹ (cc.mil/cm².hr.atm)expressed as per atmosphere of hydrostatic or osmotic pressuredifference across the semipermeable wall. The polymers are known to theart in U.S. Pat. Nos. 3,845,770; 3,916,899; and 4,160,020; and inHandbook of Common Polymers by Scott, J. R. and Roff W. J., 1971,published by CRC Press, Cleveland, Ohio.

Inner wall 22, in contact with external wall 14 comprises in a presentlypreferred manufacturer gelatin. The gelatin used for the present purposecomprises a viscosity of 10 to 40 millipoises and a bloom strength up to150 grams; and gelatin comprising a bloom value of 160 to 250. The innerwall 22 can comprises 100 weight percent gelatin, or in anothermanufacturer inner wall 22 can comprises 60 wt % to 99 wt % gelatin, and1 wt % to 40 wt % of a polysaccharide selected from the group consistingof agar, acacia, karaya, tragacanth, algin and guar.

Coat 23 comprising drug 24 is coated onto the exterior surface ofsemipermeable wall 14. Coat 23 comprises an aqueous soluble carrier thatprovides instant drug 24 to a patient in from zero time to seventy-fiveminutes. Coat 23 comprises at least one member selected from the groupconsisting of hydroxyalkylcellulose, such ahydroxypropylmethylcellulose, hydroxybutylmethylcellulose,hydroxyethylmethylcellulose, and sodium carboxymethylcellulose. Coat 23carrier additionally embraces a member selected from the groupconsisting of polyvinylpyrrolidone, polyvinylalcohol,polyvinylpyrimidine, gelatin, polysaccharide, a blend ofpolyvinylpyrrolidone and gelatin, polyethylene oxide, and a blend ofpolyvinylpyrrolidone and an alkylcellulose, such as methylcellulose. Thedose of drug 24 in coat 23 is 150 nanograms to 350 milligrams.

The expressing drug 16 in compartment 15 includes a drug that produces aphysiologically or pharmacologically effect in animals including humans.The term physiologically denotes the administration of a drug to producenormal functions in a patient and the term pharmacologically denotesvariations in response to the dose of drug administered to an animal.The terms are defined in Stedman's Medical Dictionary, 1966, publishedby Williams & Wilkins, Baltimore, Md. The term drug as used herein meansthe drug is in the compartment by itself, or the drug is in thecompartment mixed with an osmotic solute, binder, dye, mixtures thereof,and the like. The drug that can be delivered includes inorganic andorganic compounds without limitation, including drugs that act on theperipheral nerves, adrenergic receptors, cholinergic receptors, nervoussystem, skeletal muscles, cardiovascular, smooth muscles, bloodcirculatory system, synoptic sites, neuroeffector junctional sites,endocrine and hormone systems, immunological system, reproductivesystem, skeletal system, inhibitory of autocoids and histamine systems.The active drug that can be delivered for acting on these animal systemsincludes depressants, hypnotics, sedatives, psychic energizers,tranquilizers, anticonvulsants, muscle relaxants, antiparkinson agents,analgesics, anti-inflammatory, local anesthetics, muscle contractants,anti-microbials, anti-malarials, hormonal agents, contraceptives,sympathomimetics, diuretics, anti-parasitics, neoplastics,hypoglycemics, ophthalmics, electrolytes, diagnostic agents andcardiovascular drugs.

Drugs 16 that act on the central nervous system include hypnotics andsedatives, including pentobarbital sodium, phenobarbital, secobarbital,thiopental and mixtures thereof; heterocyclic hypnotics such asdioxopiperidines and glutarimides; hypnotics and sedatives such asamides and ureas, exemplified by diethylisovaleramide anda-bromoisovaleryl urea; hypnotic and sedative urethanes and disulfanes;psychic energizers such as isocoboxazid, nialamide, phenelzine,imipramine, tranylcypromine and parglyene; tranquilizers such aschloropromazine, promazine, fluphenazine, reserpine, deserpidine,meprobamate, and benezodiazepines such as chlordiazepoxide;anticonvulsants such as primidone, enitabas, diphenylhydantoin,ethotoin, pheneturide and ethosuximide; muscle relaxants andantiparkinson agents such as mephenesin, methocarbomal, trihexlphenidyl,and biperiden; anti-hypertensives such as methyldopa andL-β-3-4-dihydroxyphenylalanine, and pivaloyloxyethyl ester ofα-methyldopa hydrochloride dihydrate; analgesics such as morphine,codeine, meperidine, nalorphine, antipyretics and anti-inflammatoryagents such as aspirin, indomethacin, salicylamide, naproxen, colchicinefenoprofen, sulidac, diclofenac, indoprofen and sodium salicylamide,local anesthetics such as procaine, lidocaine, maepaine, piperocaine,tetracaine and dibucane; antispasmodics and muscle contractants such asatropine, scopolamine, methscopolamine, oxyphenonium, papaverine;prostaglandins such as PGE₁ PGE₂, PGE₁₈, PGE₂₈ and PGA; anti-microbialssuch as penicillin, tetracycline, oxytetracycline, chlorotetracycline,chloramphenicol and sulfonamides; anti-malarials such as4-aminoquinolines, 8-aminoquinolines and pyrimethamine; hormonal agentssuch as prednisolone, cortisone, cortisol and triamcinolone, androgenicsteroids such as methyltesterone, and fluoxmesterone; estrogenicsteroids such as 17β-estradiol, α-estradiol, estriol, α-estradiol3-benzoate, and 17-ethynyl estradiol-3-methyl ether; progestationalsteroids such as progesterone, 19-nor-pregn-4-ene-3,20-dione,17-hydroxy-19-nor-17-α-pregn-5(10)-ene-20-yn-3-one,17α-ethynyl-17-hydroxy-5(10)-estren-3-one, and9β10α-pregna-4,6-diene-3,20-dione; sympathomimetic drugs such asepinephrine, amphetamine, ephedrine and norepinephrine; hypotensivedrugs such as hydralazine, cardiovascular drugs such as procainamide,procainamide hydrochloride, amyl nitrite, nitroglycerin, dipyridamole,sodium nitrate and mannitol nitrate; diuretics such as chlorothiazide,acetazolamide, methazolamide and flumethiazide; antiparasitics such asbephenium, hydroxynaphthoate, dichlorophen and dapsone; and neoplasticssuch as nechlorethamine, uracil mustard, 5-fluorouracil, 6-6-thioguanineand procarbazine; a lipid regulating agent including gemfibrozilβ-blockers such as pindolol, propranolol, practolol, metoprolol,oxprenolol, timolol, atenolol, alprenolol, and acebutolol; hypoglycemicdrugs such as insulin, isophane insulin, protamine zinc insulinsuspension, globin zinc insulin, extended insulin zinc suspension,tolbutamide, acetohexamide, tolazamide and chlorpropamide; antiulcerdrugs such as cimetidine; nutritional agents such as ascorbic acid,niacin, nicotinamide, folic acid, choline, biotin, pantothenic acid, andvitamin B₁₂; essential amino acids; essential fats; eye drugs such aspilocarpine, pilocarpine salts such as pilocarpine nitrate, pilocarpinehydrochloride, dichlorphenamide, atropine, atropine sulfate, scopolamineand eserine salicylate; histamine receptor antagonists such ascimetidine; and electrolytes such as calcium gluconate, calcium lactate,potassium chloride, potassium sulfate, sodium chloride, potassiumfluoride, sodium fluoride, ferrous lactate, ferrous gluconate, ferroussulfate, ferrous fumarate and sodium lactate; and drugs that act onα-adrenergic receptors such as clonidine hydrochloride. Drug 16, inanother manufacture, is an antiviral drug for treating viral injectionscomprising a member selected from the group consisting of didanosine,zidovardine, zalcitabine, acyclovir, fluxuridine, ribavirin, cytarabine,vidarabine, azidouridine, ganciclovir, deoxynojirmycin, fiacitabine,fialuridine, fluorothymidine, dideoxycitidine, nevirapine, staviudine,dideoxyinosine, isoprinosine, and foscarnet. The beneficial drugs 16 areknown to the art in Remington's Pharmaceutical Sciences, 14th Ed., 1970,published by Mack Publishing Co., Easton, Pa.; and in ThePharmacological Basis of Therapeutics, by Goodman and Gilman, 4th Ed.,1970, published by the MacMillan Company, London, and in U.S. Pat. No.4,576,604.

Drug 16 can be in various therapeutic forms, such as unchargedmolecules, molecular complexes, pharmacologically acceptable salts suchas inorganic, organic, hydrochloride, hydrobromide, sulfate, laurylate,palmitate, phosphate, nitrite, oleate and salicylate. For acid drugs 24,salts of metals, amines, or organic cations, quaternary ammoniumderivatives can be used for the presence purpose. Derivatives of drug16, such as an ester, ether and amide can be used for the presentpurpose. A drug that is water insoluble can be used in a form that is awater soluble derivative thereof to effectively serve as a solute, andon its administration form osmotic caplet 10, it is converted byenzymes, hydrolyzed by the body pH or other metabolic processes to theoriginal drug form, or to a biologically active form. Drug 24 in coat 23can be the same as drug 16 in compartment 15, or drug 24 in coat 23 canbe a different drug 24 than drug 16 in compartment 15. Generally,compartment 15 comprises 300 nanograms, ng, to 1200 milligrams, mg, ofdrug 16 for administered at 5 ng to 850 mg over a prolonged period up to24 hours, hrs. In another embodiment, individual osmotic caplet 10 canbe provided comprising 1 mg, 5 mg, 50 mg, 100 mg, 125 mg, 200 mg, 275mg, 500 mg and 650 mg. The osmotic caplet 10 can be administered once,twice or thrice daily.

The osmagent 17 that can be used for the purpose of this inventioncomprise inorganic and organic, preferably a solid compound thatexhibits an osmotic pressure gradient across an external fluid acrosssemipermeable wall 14. The osmagents are known also as osmoticallyeffective compounds, osmotic solutes, and osmotic fluid imbibing agents.The osmagents are used by mixing the osmagent with drug 16 that has alimited solubility in the external fluid to provide an osmotic solidcomposition, that after fluid is imbibed into caplet, an osmotic drugsolution that is hydrodynamically and osmotically delivered from osmoticcaplet 10. The phrase limited solubility as used herein means the drughas a solubility of less than 1% by weight in an aqueous fluid presentin the environment. The osmagents are used by homogenously orheterogenously mixing the osmagent with the drug and then changing theblend into a caplet or pressing the blend into a shape corresponding tothe shape of osmotic caplet 10, which is then surrounded withsemipermeable wall 14. The osmagent attracts fluid into caplet 10producing a solution which is delivered from the caplet concomitantlytransporting undissolved and dissolved drug to the exterior of caplet10. Osmagent 17 used for the purpose of this invention comprises amember selected from the group consisting of a salt, oxide,carbohydrate, acid, ester, magnesium sulfate, magnesium chloride, sodiumchloride, potassium chloride, lithium chloride, potassium sulfate,sodium sulfate, lithium sulfate, lithium phosphate, sodium phosphate,potassium phosphate, potassium acid phosphate, calcium lactate,mannitol, urea, inositol, magnesium succinate, tartaric acid,carbohydrates such as raffinose, sucrose, glucose, lactose monohydrate,and a blend of fructose glucose.

The osmagent is initially present in excess and it can be any physicalform such as particle, crystal, pellet, tablet, strip, film or granule.The osmotic pressure of saturated solutions of various osmoticallyeffective compounds and for mixtures of compounds at 37° C., in water,is listed in Table 1. In the table, the osmotic pressure π, is inatmospheres, ATM. The osmotic pressure is measured in a commerciallyavailable osmometer that measures the vapor pressure difference betweenpure water and the solution to be analyzed, and according to standardthermodynamic principles, the vapor pressure ratio is converted intoosmotic pressure difference. In Table 1, osmotic pressures of from 20ATM to 500 ATM are set forth; of course, the invention includes the useof lower osmotic pressures from zero, and higher osmotic pressures thanthose set forth by way of example in Table 1. The osmometer used for thepresent measurements is identified as Model 320B, Vapor PressureOsmometer, manufactured by Hewlett Packard Co., Avondale, Pa.

OSMOTIC PRESSURE COMPOUND OR MIXTURE ATM Lactose-Fructose 500Dextrose-Fructose 450 Sucrose-Fructose 430 Mannitol-Fructose 415 SodiumChloride 356 Fructose 355 Lactose-Sucrose 250 Potassium Chloride 245Lactose-Dextrose 225 Mannitol-Dextrose 225 Dextrose-Sucrose 190Mannitol-Sucrose 170 Dextrose  82 Potassium Sulfate  39 Mannitol  38Sodium Phosphate Tribasic.12H₂O  36 Sodium Phosphate Dibasic.7H₂O  31Sodium Phosphate Dibasic.12H₂O  31 Sodium Phosphate Dibasic Anhydrous 29 Sodium Phosphate Monobasic.H₂O  28

The osmopolymer 17, operable for pushing drug 17 composition from caplet10 comprises a hydrophilic polymer. Hydrophilic polymers are known alsoas osmopolymers. The osmopolymers interact with water and aqueousbiological fluids and swell or expand to an equilibrium state. Theosmopolymers exhibit the ability to swell in water and retain asignificant portion of the imbibed water within the polymer structure.The osmopolymers swell or expand to a very high degree, usuallyexhibiting a 2 to 60 fold volume increase. The osmopolymers can benoncross-linked or cross-linked. The swellable, hydrophilic polymersare, in one presently preferred embodiment, lightly cross-linked, suchas cross-links being formed by covalent or ionic bonds. The osmopolymerscan be of plant, animal or synthetic origin. Hydrophilic polymerssuitable for the present purpose include poly(hydroxyalkylmethacrylate)having a molecular weight of from 30,000 to 5,000,000;poly(vinylpyrrolidone) having molecular weight of from 10,000 to360,000; anionic and cationic hydrogels; polyelectrolyte complexes,poly(vinyl alcohol) having a low acetate residual, cross-linked withflyoxal, formaldehyde, or glutaraldehyde and having a degree ofpolymerization from 200 to 30,000; a mixture of methyl cellulose,cross-linked agar and carboxymethyl cellulose; a water insoluble, waterswellable copolymer reduced by forming a dispersion of finely dividedcopolymer of maleic anhydride with styrene, ethylene, propylene,butylene or isobutylene cross-linked with from 0.00001 to about 0.5moles of polyunsaturated cross-linking agent per mole of maleicanhydride in the copolymer; water swellable polymers of N-vinyl lactams,and the like.

Other osmopolymers include hydrogel polymers such as Carbopol® acidiccarboxy polymers generally having a molecular weight of 450,000 to4,000,000; the sodium salt of Carbopol® acidic carboxy polymers andother metal salts; Cyanamer® polyacrylamides; cross-linked waterswellable indenemaleic anhydride polymers; Goodrite® polyacrylic acidhaving, but not limited to, a molecular weight of 80,000 to 200,000, andthe sodium and other metal salts; Polyox® polyethylene oxide polymershaving a molecular weight of 100,000 to 7,500,000; starch graftcopolymers; Aqua-Keeps® acrylate polymers; diester cross-linkedpolyglucan, and the like. Representative polymers that form hydrogelsare known to the prior art in U.S. Pat. No. 3,865,108 issued to Hartop;U.S. Pat. No. 4,002,173 issued to Manning; U.S. Pat. No. 4,207,893issued to Michaels, in U.S. Pat. No. 4,576,604 issued to Guittard etal.; in U.S. Pat. No. 4,855,141 issued to Eckenhoff et al.; and inHandbook of Common Polymers, by Scott and Roff, published by theChemical Rubber, CRC Press, Cleveland, Ohio.

The solubility of a drug in the fluid can be determined by knowntechniques. One method consists of preparing a saturated solutioncomprising the fluid plus the drug as ascertained by analyzing theamount of agent present in a definite quantity of the fluid. A simpleapparatus for this purpose consists of a test tube of medium sizefastened upright in a water bath maintained at constant temperature andpressure, in which the fluid and the drug are placed and stirred by arotating glass spiral. After a given period of stirring, a weight of thefluid is analyzed and the stirring continued an additional period oftime. If the analysis shows no increase of dissolved drug aftersuccessive periods of stirring, in the presence of excess solid drug inthe fluid, the solution is saturated and the results are taken as thesolubility of the product in the fluid. If the drug is soluble, an addedosmotically effective compound optionally may not be needed; if the drughas limited solubility in the fluid, then an osmotically effectivecompound can be incorporated into the device. Numerous other methods areavailable for the determination of the solubility of a drug in a fluid.Typical methods used for the measurement of solubility are chemical andelectrical conductivity. Details of various methods for determiningsolubilities are described in United States Public Health ServiceBulletin, No. 67 of the Hygienic Laboratory; Encyclopedia of Science andTechnology, Vol. 12, pp 542 to 556, 1971, published by McGraw-Hill,Inc.; and Encyclopedia Dictionary of Physics, Vol. 6, pp 547 to 557,1962, published by Pergamon Press, Inc.

The present invention manufactures an osmotic caplet 10 by surrounding apressed solid caplet-shaped solid body 11 with a semipermeable wall 14,or first with a gelatin wall 22 followed by a semipermeable wall 14. Onemethod of manufacture comprises inserting a pressed body into a capletchannel machine leaving one end exposed that is dipped into awall-forming bath to coat the exposed end, followed by dipping the otheruncoated end into the bath to surround the end with a wall-formingcomposition. In one manufacture, the caplet is coated with asemipermeable wall and then permitted to dry with rotation for spreadingevenly the wall-forming semipermeable wall around the body of thecaplet. In another manufacture, a gelatinous coating is applied to thefirst end and then to the second end of the body of the caplet. Next,after the caplet is permitted to dry and then followed by coating thebody of the caplet in a semipermeable wall-forming bath. Inner wall 22can in another manufacture comprise a coating consisting of a watersoluble polymer such as a hydroxyethylcellulose,hydroxypropylmethylcellulose and hydroxypropylcellulose. Inner wall 22in this manufacture serves as a lubricating wall 22 to facilitate highdrug loading of osmotic caplet 10 and to facilitate the uninhibitateddelivery of drug 16 from osmotic caplet 10. That is, lubricating wall 20substantially eliminates resistance of drug 16 delivery from osmoticcaplet 10.

Another manufacture comprises filling a caplet die with the compositionto be compressed into a shape corresponding to the die cavity, and thenremoving the compressed body from the cavity. The die cavity islubricated prior to filling the cavity to present sticking and to makeit easy to remove the compressed caplet-shaped body from the die cavity.The die cavity may be lubricated with a lubricant such as stearic acid,magnesium stearate, calcium stearate, sodium lauryl sulfate or potassiumlauryl sulfate. Next, the caplet body is surrounded with a wall. A wallcan be applied by using standard wall-coating equipment. Equipment thatcan be used for coating the compressed body include the Accela-Cote®coater, High-Cota® or the Wurster® suspension coater. The coaters oftencomprise a vaporizer to facilitate drying, and an exhaust systemdesigned to remove any possible dust. The coating can be effected byusing spray guns, and atomizing equipment to introduce a wall-formingsolution into a coating pan, or to introduce a wall-forming solutioninto an air suspension column. Optionally, cold or warm air can beintroduced into the spraying cycle to regulate coating and/or drying ofthe coated caplet. The coating solution can be applied by using aperistaltic spray pump or a pneumatic displacement pump, in continuousor interrupted spray and dry patterns. The coating composition issprayed to a preselected desired thickness, usually for each separatewall 0.25 mm to 10 mm.

Another manufacture that can be used for coating a pressed caplet body,previously pressed in a plate process, rotary die process, areciprocating die process, or a continuous rotary press, or highpressure station rotary press, or high pressure station rotary press, inone manufacture comprises placing a caplet-forming film over a lowermold with the caplet forming formulation poured onto the film. Then, afilm of a wall-forming composition is placed over the caplet bodyfollowed by the top mold. The mold set is placed under a press andpressure applied with or without heat to form the caplet. The caplet canbe made with a passageway. The passageway is integrally formed by themold set equipped with a passageway-forming area that presents coatingin the passageway area.

Another manufacture of caplet 10, is manufactured by standardgranulation techniques. For example, the caplet forming ingredients areformulated by the wet granulation technique using an organic cosolvent,such as isopropyl alcohol-methylene dichloride, 80/20, v/v,(volume/volume) as the granulating fluid. The ingredients forming thecaplet comprising the drug and other caplet forming ingredients areindividually passed through a 40 mesh screen and then thoroughly blendedin a blender. Next, a polymer, for example, poly(vinylpyrrolidone) isdissolved in a portion of granulation fluid, in the cosolvent describedabove. Then, the poly(vinylpyrrolidone) solution is slowly added to thedry powder blend with continual mixing in a blender. The granulationfluid is added until a wet blend is produced, generally about 400 cc ofgranulating fluid per kilogram of blend. The wet mass blend then isforced through a 20 mesh screen onto trays and dried for 18 to 30 hoursat 40° C. to 60° C. The dried granules are sized with a mesh screen.Next, a lubricant such is magnesium stearate is added to the dryscreened granular blend, and the blend passed through an 80 mesh screen.

In another process the drug and other caplet-forming compositions areblended in a fluid bed granulation. After the powders are dry blended, agranulation fluid comprising an aqueous granulation fluid is sprayedonto the powders an dried in a granulation. This process granulates allof the ingredients together while adding the granulation solution. Afterthe granules are dried, a lubricant such as magnesium stearate is addedto the granulation.

The caplet forming blend, in either of the above processes, is thenpressed into a caplet using a tablet press. The speed of the press isset optionally at 30 rpm and the maximum load set at 0.5 to 20 tons.Then, the caplet body is surrounded with a wall.

The osmotic caplet, in another manufacture is made by mixing a drug withan osmagent and/or an osmopolymer, and pressed into a solid possessingdimensions that corresponds to the internal dimensions of the caplet; orthe drug and other caplet formulation forming ingredients and a solventare mixed by conventional methods such as ballmilling, calendering,stirring or rollmilling, and then pressed into a preselected shape.Next, a layer of a composition comprising an osmagent, and/or anosmopolymer is placed in contract with a layer of drug formulation, andthen the two contacting layers, except for a caplet mouth, aresurrounded with a semipermeable wall. The wall can be applied byprotecting the caplet mouth to keep it open free from coating with asemipermeable wall forming material. The wall can be applied by molding,spraying, or dipping the pressed shapes into wall-forming materials.Another and presently preferred technique that can be used for applyingthe wall is the air suspension coating procedure. This procedureconsists in suspending and tumbling the pressed compositions in acurrent of air and a wall forming composition until the wall surroundsand coats the two pressed compositions. The air suspension procedure isdescribed in U.S. Pat. No. 2,799,241; J. Am. Pharm. Assoc. Vol. 48, pp451-59 (1979); and, ibid, Vol. 49, pp 82 to 84 (1960). Other standardmanufacturing procedures are described in Modern Plastics Encyclopedia,Vol. 46, pp 62 to 70 (1969); and in Pharmaceutical Science, byRemington, 14th Ed., pp 1626 to 1978 (1970), published my MackPublishing Co., Easton, Pa.

Exemplary solvents suitable for manufacturing include inert inorganicand organic solvents that do not adversely harm the materials and thefinal. The solvents broadly include members selected from the groupconsisting of aqueous solvents, alcohols, ketones, esters, ethers,aliphatic hydrocarbons, halogenated solvents, cycloaliphatichydrocarbons, halogenated solvents, cycloaliphatics, aromatics,heterocyclic solvents and mixtures thereof. Typical solvents includeacetone, diacetone alcohol, methanol, ethanol, isopropyl alcohol, butylalcohol, methyl acetate, ethyl acetate, isopropyl acetate, n-butylacetate, methyl isobutyl ketone, methyl propyl ketone, n-hexane,n-heptane, ethylene glycol monoethyl ether, ethylene glycol monoethylacetate, methylene dichloride, ethylene dichloride, propylenedichloride, carbon tetrachloride, chloroform, nitroethane, nitropropane,etrachloroethane, ethyl ether, isopropyl ether, cyclohexane,cyclooctane, benzene, toluene, naphtha, 1,4-dioxane, tetrahydrofuran,diglyme, aqueous and nonaqueous mixtures thereof, such as acetone andwater, acetone and methanol, acetone and ethyl alcohol, methylenedichloride and methanol, and ethylene dichloride and methanol.

DETAILED DESCRIPTION OF EXAMPLES

The following examples are illustrative of the present invention, andthey should not be considered as limiting the scope of the invention inany way, as these examples and other equivalents thereof will becomeapparent to those versed in the art in the light of the presentdisclosure, the drawings and the accompanying claims.

Example 1

An osmotic oblong-shaped solid caplet is manufactured with a wide,passageway as follows: first, 300 mg of ranitidine hydrochloride, ahistamine H₂ receptor antagonist for inhibiting both daytime andnocturnal basal gastric acid secretion, including gastric acid secretionstimulation is blended with 11.0 mg of hydroxypropylmethylcellulosehaving a 11,200 molecular weight, 27 mg of microcrystalline cellulosehaving a 0.09 mm particle size and a 36,000 molecular weight, 36 mg ofpolyvinylpyrrolidone having a 35,000 molecular weight, and 5 mg ofmagnesium stearate, are dry blended for 17 to 20 minutes in a blender toproduce a homogenous blend. Next, the dry blend is wetted with 350 mL ofanhydrous ethanol, followed by drying the blend in an oven for 20 hoursat 30° C. Next, the dried granules are passed through a 20 mesh screen,and compressed under 2.5 tons in an oblong-shaped dye to yield a solidcaplet-shaped composition.

Next, the pressed composition is inserted into a caplet-retaining memberthat covers the caplet in the passageway-forming area and simultaneouslypermits the body of the caplet exposed for receiving a wall-formingcomposition.

Next, the exposed caplet body is surrounded with a permeablewall-forming composition by dipping the exposed surface into thecomposition. The wall-forming composition comprises 55 wt % celluloseacetate comprising an acetyl content of 39.8%, 43 wt %polyvinylpyrrolidone having a 42,000 molecular weight, and 2 wt %tripropyl citrate are dissolved in a cosolvent comprising methylenechloride-methanol, 85 wt %-15 wt %, to obtain 5% solids. Thewall-forming composition is coated around the opposed caplet by dryinguntil a uniform wall is applied, to about 5.5 mg per wall.

Finally, the osmotic caplet is removed from the caplet-holding member,and dried in a forced air oven at 50° C. for 50 hours to evaporate thesolvents. The osmotic caplet comprises an orifice opening of 0.1 of thearea of the cylindrical cross-section of the caplet.

Example 2

The procedure of Example 1 is repeated in this example with all themanufacturing steps as previously set forth, except that in this examplethe permeable wall is coated on its exterior surface with an instantrelease ranitidine salt coat. The instant coat is applied to theexterior semipermeable wall from a composition comprising 60 mg ofranitidine hydrochloride, 120 mg of mannitol, and 120 mg ofhydroxypropylmethylcellulose having a 11,200 molecular weight indistilled water, and dried to yield an instant release coat. The osmoticcaplet provides instant release ranitidine therapy from the exteriorcoat followed by ranitidine therapy from inside the osmotic caplet.

Example 3

An osmotic caplet is provided to produce an oral, osmotic capletproviding the procedures of Examples 1 and 2, wherein the osmotic capletcomprises 20 mg of famotidine, a competitive inhibitor of histamine H₂on the exterior surface and 125 mg of famotidine inside the osmoticcaplet.

Example 4

An,osmotic caplet for dispensing cimetidine to a patient in need ofcimetidine therapy is prepared as follows: first, 35 kg of cimetidinehydrochloride is passed through a sizing screen and then added to thebowl of a fluid bed granulator. Next, 1.46 kg of polyvinylpyrrolidonehaving a 360,000 molecular weight is mixed with distilled water and thefluid prepared is fed into the granulator in small volumes to dampen thecimetidine hydrochloride. The resulting granulation is dried and passedthrough a standard 20 mesh screen. Next, 0.178 kg of magnesium stearateis added to the granules and blended with the granules. The granules arefed to a caplet dye and pressed under 2.5 tons of pressure into acaplet-shaped solid dosage form. The caplet comprises cimetidinehydrochloride 87.3 wt %, 6.3 wt % polyvinylpyrrolidone, 0.5 wt %magnesium stearate, and 5.9 wt % bound water.

Next, the caplet-shaped solid dosage is inserted into a hollow, caplethousing member that both holds the caplet and covers its lead end toprovide a caplet passageway formed during coating the remainder of thecaplet with semipermeable wall. The semipermeable composition comprises50 wt % cellulose acetate comprising 39.8% acetyl content ishomogeneously blended with 40 wt % polyvinylpyrrolidone comprising a42,000 molecular weight, and 8 wt % hydroxypropylmethylcellulose ismixed with an acetone-methyl alcohol cosolvent 80 wt %-20 wt %,comprising 6% solids, and mixing continued until a clear solutionresets. Next, the compressed caplets in the housing member are placed ina coater, and the caplets coated on the exposed areas with thewall-forming composition. A wall comprising 39.7 mg of celluloseacetate, 30.7 mg of polyvinylpyrrolidone, 6.5 mg ofhydroxypropylmethylcellulose and 1.5 mg of tripropyl citrate is coatedto each exposed caplet. The wall composition weighed 78.4 mg. The coatedcaplets are removed from the coater a convex lead end with a 1 mmpassageway, and a cross-section of 8 mm. The osmotic caplet delivery thecimetidine in the upper gastrointestinal tract.

Example 5

The procedure of Example 4 is followed in this example, except in thisexample, the osmotic caplet comprises a dose amount of a drug selectedfrom the group consisting of omeprazole, nizatidine, bifentidine,erbrotidine, nifentidine, roxatidine and lansoprazole.

Example 6

An osmotic caplet comprising 50 mg of carbidopa, an inhibitor ofaromatic amino acid decarboxylation, and 200 mg of levodopa themetabolic precursor of dopamine that crosses the blood-brain barrier andis converted, to dopamine for the treatment of Parkinson's disease isprepared by blending the carbidopa and levodopa with 150 mg ofpoly(ethylene oxide) having a 200,000 molecular weight, 30 mg ofhydroxypropylmethylcellulose stearate, and 18 mg of microcrystallinecellulose having a 36,000 molecular weight, are blended into ahomogenous mass and passed through a 40 mesh screen. Next, 1 mg ofmannitol is passed through a mesh screen and all the screenedingredients are added to the bowl of a laboratory blender and theingredients dry blended for 20 minutes to produce a homogenous blend.Then, a granulation fluid is prepared comprising 250 mL of ethanol and250 mL of isopropyl alcohol by stirring the solvents, and thegranulation fluid added to the bowl of the blinder. Then, 20 mL of thegranulating fluid is sprayed into the bowl with constant blending, then35 mL of the granulation fluid is added and the mess blended for 15 to20 minutes. Then, the wet granules are passed through a 16 mesh screenand dried at room temperature for 24 hours.

Next, a second osmotic push composition is prepared by blending 55 mg ofpoly(ethylene oxide) having a 5,000,000 molecular weight, mg of sodiumchloride and 1.5 mg of magnesium stearate are passed through a 40 meshscreen, and the ingredients added to a mixing bowl, and all theingredients blended for 10 to 15 minutes. Then, a granulation fluid isprepared by mixing 75 mL of methanol and 150 mL of isopropyl alcohol,and the granulation fluid slowly added to the bowl and the wet blendmixed for 15 to 20 minutes to produce a homogenous blend. Next, the wetblend is passed through a 16 mesh screen, spread on a stainless steeltray and dried at room temperature of 22.5° C. for 24 hours.

A number of solid caplet cores are prepared by pressing the twocompositions comprising the drug composition and the expandable, pushcomposition in a caplet cavity mold and compressing the two layers intoan oblong shape. Next, the caplet cores lead end one placed into acaplet mold and the exposed surface coated with a permeable polymericcomposition comprising cellulose acetate having a 39.8% acetyl content,poly(ethylene glycol) 4,000, methylene chloride and methanol. Thecaplets are coated in their uncoated area until this area is coated witha wall. A Wurster® air suspension coated caplets are removed from thecaplet mold and then spread on a tray. The solvent is evaporated in acirculating air oven at 50° C. for 60 hours. The osmotic caplet isadministered orally to a patient in need of treating Parkinson'sdisease.

Example 7

The procedures of the above examples are followed in this example, toprovide an osmotic caplet comprising a convex curved lead end defining acaplet passageway, and wherein the osmotic caplet comprises a memberselected from the group consisting of biperiden hydrochloride, biperidenlactate, trihexyphenidyl hydrochloride, diphenhydramine hydrochloride,benztropine mesylate, procyclidine hydrochloride, selegiline additionsalt, selegiline hydrochloride, selegiline palmate, hyoscyamine sulfate,and hyoscyamine hydrobromide.

Example 8

An osmotic caplet comprising a convex wall formed by the wall bulgedoutward at the lead end and comprising an exit port in the convex wallis prepared as follows: first, 160 mg of tandospirone, and 120 mg ofpoly(ethylene oxide having a 200,000 molecular weight are added to aFreund Flo-Coater's® bowl, a fluid bed granulator, and the drug and thepolymer mixed in an air suspension for 5 minutes to produce a homogenousblend. Next, a solution prepared by dissolving 100 g ofpoly(vinylpyrrolidone) having a 27,500 molecular weight and 1,566 g ofwater are sprayed onto the homogenous blend. Next, the coated blend wasdried, and the granules removed from the granulator. Next, the granulesare mixed with 2.25 mg of calcium stearate and 0.25 mg of butylatedhydroxytoluene, to produce caplet granules.

Next, a push composition is prepared by blending 130 mg of poly(ethyleneoxide) comprising a 7,500,000 molecular weight, 35 mg of osmagent sodiumchloride, and 0.6 mg of ferric oxide are separately screened through a40 mesh screen and then blended into a homogenous blend. Next, 30 mg ofhydroxypropylmethylcellulose having a 11,200 molecular weight is blendedwith the screened, homogenous blend to produce a resultant blend. Thislatter lend is mixed with 30 mg of denatured, anhydrous alcohol, for 5minutes, passed through a 20 mesh screen, allowed to dry at 22° C. for10 hours, and again passed through a 20 mesh screen. The screened pushcomposition is blended with 0.25 mg of magnesium stearate, and screenedto produce the granules.

Next, the tandospirone drug composition and the pushosmopolymer-osmagent composition are compressed in contacting bilayeredarrangement in a caplet dye. The compositions are compressed in thelength or vertical direction of the caplet to provide a convex, curvedbulged outward lead end and a curved trailing end. The two contactingcompositions are compressed under a pressure of two tons.

Next, the caplet body is inserted into a caplet holder that covers thelead end and permits the remainder of the caplet body to be exposed forreceiving a gelatin coat. The gelatin coat comprises gelatin,erythrosin, iron oxide and titanium dioxide in an aqueous carrier. Theexposed surfaces are coated with a thin 0.1 mm coat. Other gelatincoats, from 0.1 mm to 7.5 mm can be coated onto the caplet surface. Thegelatin coat is overcoated with a laminated semipermeable wallcomposition comprising cellulose acetate having an acetyl content of 32%using an air suspension coater. The semipermeable wall formingcomposition comprises 5% polymer in acetone-water, 90:10, wt/wt, is usedto form the semipermeable wall 0.07 mm thick. The osmotic caplet isremoved from the caplet holder, and dried to evaporate the solvents.

Example 9

The above examples are followed in this example for manufacturing anosmotic caplet comprising a lead end possessing a semipermeable bulgedwall having a wide passageway with the caplet comprising 25 mg to 750 mgof a drug selected from the group consisting of quinapril, indolapril,olindapril, rentiapril, spirapril, cilazaprilat, lisinopril, imidapril,benazeprilat, cilazapril, alacepril, captopril, delapril, fosinopril,libenzapril, pentopril, perindopril, altiopril, quinaprilat, ramipril,spiraprilat, teprotide, zofenopril, enalapril, benazepril, enalaprilat,antipain, and cilastatin.

Example 10

An elongated dosage form is manufactured as an osmotic caplet comprisinga length of 22 mm and a diameter of 8.5 mm at its center, and a curvedlead end comprising a caplet passageway is manufactured according to theprocesses of this invention, with the caplet comprising 15 mg to 750 mgof a drug selected from the group consisting of amrinone, bepridil,diltiazem, felodipine, fendiline, flunarizine, nicardipine, isradipine,nifedipine, nimodipine, nisoldipine, nitredipine, perhexiline,amlodipine, nilvadipine, prenylamine, verapamil, cinnarizine,gallopamil, belfosdil, and fostedil.

Example 11

The manufacturing procedure in the above examples are followed toprovide an osmotic caplet comprising 500 ng to 1000 mg of antiviral drugselected from the group consisting of didanosine, zidovudine,zalcitabine, acyclovir, fluxuridine, ribavirin, cytarabine, vidarabine,azidouridine, ganciclovir, deoxynojirmycin, fiacitabine, fialuridine,fluorothymidine, foscarnet, dideoxycitidine, nevirapine, staviudine,dideoxyinosine, and, isoprinosine.

Example 12

An osmotic caplet is prepared as follows: first, a drug compositioncomprising 525 mg of the insoluble base drug nifedipine is blended with140 mg of poly(ethylene oxide) having a 175,000 molecular weight, and7.5 mg of sodium chloride to produce a uniform blend. Then 0.75 mg ofcalcium stearate is added to the blend, all the ingredients blended, andscreened through a 40 mesh screen to produce uniform particles. Next, acaplet displacement composition is prepared comprising 70 mg of sodiumcarboxymethylcellulose, 10 mg of sodium chloride and 1 mg of magnesiumstearate are blended for minutes in a stainless steel blender. Next, theblend is screened through a 40 mesh screen to yield caplet displacementparticles. Then, the drug particles and the displacement particles aredried separately, and the two respective particle composition pressedinto contacting layers under pressure of 3.25 tons.

The pressed layers are next inserted into a caplet mold and the exposedcaplet body sprayed with a wall-forming composition comprising 80 wt %cellulose acetate having a 43.3% acetyl content, 7.5 wt % ofhydroxypropylmethylcellulose comprising a 9,200 molecular weight, 10 wt% of poly(vinylpyrollidone) having a 39,000 molecular weight, and 2.5 wt% of tributyl citrate in a methylene chloride-ethanol to surround theexposed caplet body with a semipermeable wall. The wall is permeable toaqueous fluids and impermeable to drug. The osmotic caplet comprises alarge osmotic caplet orifice to effect the delivery of essentially allof the drug. The osmotic caplet is free of the need for drug overloading because essentially all the drug is delivered from the osmoticcaplet. In contrast, a noncaplet dosage form requires excess drug todeliver a given dose of drug to compensate for the drug retained in thenoncaplet dosage form. Moreover, the osmotic caplet exhibits instantdrug delivery from the caplet, and is essentially free of the delayknown to the prior at delivery system.

Example 13

An embodiment of this invention pertains to the use of aneasy-to-swallow osmotic caplet in a method for administering a drug tothe gastrointestinal tract of a patient in need of drug therapy, whereinthe use of the osmotic caplet comprises: (1) admitting the osmoticcaplet orally into the patient in need of therapy, the osmotic capletcomprising: (a) an oblong body; (b) a dose amount of 10 mg to 750 mg ofdrug in the caplet; (c) a semipermeable wall defining the caplet; saidcaplet characterized by: (d) a convex lead end comprising a passagewayas means for maximizing the delivery of drug from the caplet; (2)imbibing fluid through the semipermeable wall into the caplet; thereby(3) delivering the drug to the patient to provide the needed therapyover a prolonged period of time up to 24 hrs. The easily swallowedosmotic caplets and their solid content are essentially free fromtampering and provide uniformity and precision of the dosageadministered to the patient. Examples of drugs that can be administeredinclude a member selected from the group consisting of acetaminophen,aspirin, acyclovir, gemfibrozil, ibuprofen, naproxen, methyldopa,carbidopa, levodopa, selegiline, zidovudine, didanosine, anddideoxycitidine. In summary, it will be appreciated the presentinvention contributes to the drug dispensing art by providing anunobvious and unique dosage form that possesses a practical utility, andcan administer a drug at a metered release rate up to 24 hours forpreselected therapy.

While the invention has been described and pointed out in detail withreference to operative embodiments thereof, it will be understood bythose skilled in the art that various changes, modifications,substitutions and omissions can be made without departing from thespirit of the invention. It is intended, therefore, that the inventionembraces those equivalents within the scope of the claims which follow.

We claim:
 1. An osmotic caplet for delivering a maximum dose of a drugto a patient, the osmotic caplet comprising: (1) a cylinder body; (2) adose of 300 ng to 1,200 mg of drug in the caplet; (3) a semipermeablewall that defines the caplet; and, wherein the osmotic caplet ischaracterized by: (4) a lead end comprising a convex surface with apassageway for substantially eliminating residual drug inside thecaplet, which convex surface possesses a radius of curvature equal tobut not exceeding twice the radius of the cylinder body, for maximizingthe dose of drug delivered from the osmotic caplet.
 2. The osmoticcaplet for delivering the maximum dose of drug according to claim 1,whereas the cylinder comprises a length greater that its width.
 3. Theosmotic caplet for delivering, the maximum dose of drug according toclaim 1, wherein the osmotic caplet is an osmotic solid caplet.
 4. Theosmotic caplet for delivering the maximum dose of drug according toclaim 1, wherein the drug exhibits an osmotic pressure gradient acrossthe permeable wall.
 5. An osmotic caplet for delivering a maximum doseof a drug to a patient, the osmotic caplet comprising: (1) a cylinderbody; (2) a dose of 300 ng to 1,200 mg of drug in the osmotic caplet;(3) an osmagent in the osmotic caplet; (4) a semipermeable wall thatdefines the caplet; and wherein the osmotic caplet is characterized by:(5) a convex end comprising a passageway with an inside surfacepossessing a radius of curvature r and not exceeding 2r of the cylinderbody for delivering one-hundred percent of the drug from the osmoticcaplet during the drug delivery period.
 6. The osmotic caplet fordelivering the maximum dose of drug according to claim 4, wherein thedrug is a member selected from the group consisting of cimetidine,ranitidine, famotidine, nizatidine, bifentidine, erbrotidine,nifentidine, roxatidine, omeprazole, and lansprazole.
 7. An osmoticcaplet for delivering a maximum dose of drug to a patient, said osmoticcaplet comprising: (1) a body longer in proportion to its width; (2) adose of 300 ng to 1,200 mg of drug comprising a member selected from thegroup consisting of quinapril, indolapril, olindapril, rentiapril,spirapril, cilazaprilat, lisinopril, imidapril, benazeprilat,cilazapril, alacepril, captopril, delapril, fosinopril, libenzapril,pentopril, perindopril, altiopril, quinaprilat, ramipril, spiraprilat,teprotide, zofenopril, enalapril, benazepril, enalaprilat, antipain, andcilastatin; (3) a semipermeable wall that surrounds the body; andwherein the osmotic caplet is characterized by: (4) an end comprising apassageway for eliminating drug entrapment inside the caplet, said endcomprising a convex surface with a radius of curvature r and notexceeding 2r of the caplet body width, thereby delivering the dose ofdrug from the osmotic caplet.
 8. The osmotic caplet for delivering amaximum dose of drug to a patient, according to claim 6, wherein thedrug in the osmotic caplet is replaced by a drug comprising a memberselected from the group consisting of amrinone, bencyclone, bepridil,diltiazem, felodipine, fendiline, flunarizine, nicardipine, isradipine,nifedipine, nimodipine, nisoldipine, nitredipine, perhexiline,amlodipine, nilvadipine, prenylamine, verapamil, cinnarizine, fendiline,gallopamil, belfosdil, and fostedil.
 9. An osmotic solid caplet fordelivering a dose of drug to a patient, said osmotic caplet comprising:(1) a body possessing a length in millimeters greater than its width inmillimeters; (2) a dose of 300 ng to 1,200 mg of drug in the osmoticcaplet; (3) a gelatinous coat surrounding the body; (4) a semipermeablewall surrounding the gelatinous coat; (5) an end comprising an insidesurface that eliminates residual drug retention in the osmotic caplet,said end comprising a radius of curvature r and not exceeding 2r of thewidth of the caplet body; and, (6) a passageway in the end fordelivering the drug from the osmotic caplet over a prolonged period oftime.
 10. An osmotic caplet for delivering a dose of drug to a drugreceiving environment, said osmotic caplet comprising: (1) a cylindercomprising a length greater than its width in millimeters; (2) a dose ofdrug in a first layer in the osmotic caplet; (3) a push composition in asecond layer in the osmotic caplet; (4) a wall surrounding the body; (5)an end next to the first layer integral in the permeable wall; and (6) apassageway for delivering the drug by hydro-osmotic energy from theosmotic caplet over a prolonged period of time, and wherein the osmoticcaplet is characterized by the absence of a start-up time required fordrug delivery and the end possessing a radius of curvature not exceedingthe radius of the body width for reducing residual drug in the caplet asthe end of delivering the dose of drug.
 11. The osmotic caplet fordelivering a drug according to claim 9, wherein the drug is a memberselected from the group consisting of acetaminophen, aspirin, ibuprofen,acyclovir, gemfibrozil, selegiline, methyldopa, carbidopa, and levodopa.12. The osmotic caplet for delivering a drug according to claim 9,wherein a composition comprising a drug and an immediate releasepharmaceutically acceptable carrier is in contact with the exterior ofthe semipermeable wall.
 13. An osmotic caplet for delivering a drug to apatient, said osmotic caplet comprising: (a) a cylinder; (b) a dose of300 ng to 1,200 mg of an antiviral drug in the oblong body; (c) asemipermeable wall permeable to the passage of fluid and impermeable tothe passage of drug that surrounds the oblong body; (d) a convex end fordelivering a one-hundred percent dose of antiviral drug, said convex endcomprising a radius of curvature not exceeding twice the radius of theoblong body for obtaining the desired effect.
 14. The osmotic caplet fordelivering an antiviral drug according to claim 12, wherein theantiviral drug is a member selected from the group consisting ofzidovudine, didanosine, acyclovir, and dideoxycitidine.
 15. The osmoticcaplet for delivering an antiviral drug according to claim 12, whereinthe antiviral drug is a member selected from the group consisting ofzalcitabine, fluxuridine, ribavirin, cytarabine, vidarabine,azidouridine, gancidovir, deoxynojirmycin, fiacitabine, fialuridine,fluorothymidine, foscarnet, nevirapine, staviudine, dideoxyinosine, andisoprinosine.